Today I finally had time to face the bureaucracy lion and I thought I would give an update on the findings.

After the normal notarized translation (80 quai) I went to one office to apply for the driving licence and the feedback has been that I have two choices (lucky me!):
1) Since I have already a driving licence for car I can go the standard way (the way any normal chinese citizen would go in my situation) which appears to be driving school, written and pratical exam (costly and complex)
2) Or I can go the "easy" way... cancel my current driving licence all together and apply for a new one car-moto-tricycle, doing the written exam again as everybody else has done on this forum but no practical exam. BUT this entails remaining 2 weeks without driving licence.

Given the options above I will go for the second, but not yet as I prefer to wait next week before becoming "illegal" by car.